University of Pittsburgh Department of Biological Sciences Presents
E&E Wednesday Noon Seminars 2017-2018
Graduate student Eden McQueen - University of Pittsburgh
A gene network responsible for a male genital structure also patterns a potentially coevolving female genital trait
How novel morphologies arise and evolve is a fundamental question in evolutionary biology. Animal genitalia frequently possess derived features, and it is common to see interspecific differences in both male and female genital structures. When genital features of females and males are morphometrically correlated across species, the relationship is usually assumed to be driven by selective mechanisms. An oft-overlooked explanation for concurrent changes in genital structures is pleiotropic linkage. The degree to which coevolving genital structures are genetically independent has not been elucidated in any species. We investigated the genetic underpinnings of two structures in the Drosophila melanogaster subgroup. Males in the D. melanogaster subgroup possess a novel genital outgrowth called the posterior lobe. Females of this subgroup also have a novel feature on their ovipositors called the oviscapt pouch, which appears to contact the posterior lobe during copulation. The posterior lobe and oviscapt pouch correlate in size across species, suggesting a coevolutionary relationship.
In a prior study, the gene network required for posterior lobe formation was found to have been co-opted from a larval structure during the origination of the lobe. Using gene knockdown, in-situ hybridization, antibody staining, and enhancer analysis, we investigated whether this genetic network is shared between the posterior lobe the oviscapt pouch. Surprisingly, we discovered that patterning genes from the posterior lobe network, and even the enhancers of these genes, are also involved in the developmental patterning of the oviscapt pouch. These data suggest that the necessarily-shared genetic history of males and females could in part explain the simultaneous origin and size relationship of these two sexual characters, in spite of apparent morphological distinctness. This work highlights the need to consider the role of pleiotropy in coevolutionary relationships between the sexes, a mechanism rarely investigated in the study of genital coevolution.
Wednesday, April 4, 2018
A219B Langley Hall
12:00 PM Seminar